I have talked to a couple of ICs in my life and other than giving them a brief run down of my rather dysfunctional childhood, a domineering, mean, cold, verbally abusive father, being bullied and humiliated regularly at school, we went right to the reasons I was there to talk to him or her about current issues in my life.
I already told most of my childhood that makes any difference about who I am now in this post! I've only ever talked to a couple of counselors in my life that had any common sesne, and neither of them felt there was a benefit for years of hashing over my childhood.
Rehashing it is a big waste of time and money in my opinion. I would rather have no counselor than one that wants to waste my time and money.